Preparation of latices having uniformly-sized particles, particles with a bimodal size distribution, and seeded particles is known in the art. Prior art such as U.S. Pat. No. 2,520,959 describes in general terms the use of dispersing agents and catalysts in vinyl compound polymerization. However, slow initial reactions followed by nonlinear polymerization rates are a severe deficiency of prior art emulsion polymerizations using potassium persulfate, sodium persulfate or the like. Moreover, prior art vinyl polymers frequently have poor heat stability and poor water whitening resistance. A new process is desired which overcomes these prior art deficiencies.